Tag: Organ Transplants

Back in 1999, I wrote about medical research on beagles designed to understand the problems with creating and transplanting artificial organs. Last month the researchers involved in that work announced they are now seeking regulatory approval to try out their methods in human beings.

Researchers at the Laboratory for Tissue Engineering at Boston Children’s Hospital and Harvard Medical School took bladder cells from six beagles. They then grew the bladder cells around a plastic form that mimicked the shape of the dogs’ bladders. Once the organs were fully formed, they transplanted the bladders into the dogs. After about three months, these newly grown bladders were fully functional. The dogs were monitored for more than a year with no problems emerging.

Now, Dr. Anthony Atala of Boston Children’s Hospital says he has applied to the U.S. Food and Drug Administration for approval to try this technique in human beings. Atala believes he will obtain such approval before the end of the year.

Atala will reproduce the experiment with the beagles, only this time growing a human bladder and transplanting it into a human whose bladder has been destroyed due to disease.

If that succeeds, Atala believes the sky is the limit as far as the applications for tissue engineering. “I think over time there will be no limit,” Dr. Atala told the BBC. “I think it is just a question of figuring out all the different tissue types and cell types and how they work best, but eventually I think that following the same strategies just about every organ in the body will be repairable at the very least.”

Longer term this could reduce the number of people who are on waiting lists for organ transplants, though Atala says he doesn’t believe that his technique will ever be able to completely replace organ donations. Instead it will be yet another tool that doctors will have to treat human disease.

Source:

Lab-built bladders on the way. Pallab Ghosh, The BBC, February 15, 2002.

A report in the latest issue
of Science reports that Canadian researchers were able to get human corneal
cells growing on an artificial protein surface for the first time. The
resulting organism was structurally similar to the human cornea and from
initial tests appears to function much like a human cornea.

This is a major advance for
two reasons. First, today the only place to get a new cornea is through
a transplant. Growing artificial corneas in the lab could be a huge boon
in treating vision problems — although any such use would be years off.
Second, because the artificial corneas appear to react exactly as normal
human corneas, they could be used as a substitute for animals in testing
the effect of substances on the eyes.

Alan Goldberg, director of
the Center for Alternatives to Animal Testing, told WebMD that he was
encouraged by the possibility of the artificial lenses to replace animal
tests, although he cautioned it will still take quite a bit of research
in the near future to establish for certain that tests on the artificial
corneas produce results that are adequate enough to replace animal testing.
“I’m super-encouraged,” he said, “but I’m also saying it’s not there yet.”

Even if they don’t lead
immediately to treatments in human beings, the announcement of two recent
advances in genetic engineering of organs provides more evidence of the
sort of technologies likely to hit the mainstream of medical technology
before the end of the next decade.

In mid-February researchers
announced in Science News that they had successfully transplanted
bladders grown in the lab into six beagles. The scientists grew the bladder
cells around a plastic form to make it take the shape of the bladder and
then implanted the artificial bladders in the dogs. Within three months
the artificial bladders were completely active and some of the dogs have
had the bladders for almost a year with no problems.

Obviously getting the technology
to work in human beings is a whole other problem, but these experiments
are doing for this technology what the early animal experiments on organ
transplantations did – they suggest solutions and help scientists better
understand the problems they will encounter when seeking to grow human
organs in the lab.

In a related story, Canadian
researchers are hoping to take that step of translating animal experiments
into a treatment for human beings sometime this year. Researchers there
expect for the first time to use a genetically engineered pig liver to
keep a human being alive while waiting for a liver transplant from a human
being.

Pharmaceutical company Novartis,
which has been harshly criticized by animal rights activists for its efforts
in genetic engineering, is reportedly ready to spend up to $1 billion
to develop a viable pig liver. To avoid the risk of spreading disease
from pigs to human beings, the pigs will be raised under special conditions
to assure they are disease free. The pigs are isolated from other animals
and housed in a sterile environment. The pigs are fed by hand to avoid
microbes that might pass from pig to pig while suckling.

The impetus to move forward
with this technology is especially strong in Canada which has a rather
low rate of human organ donation – only 12.1 donors per million people
compared to the U.S. with 17.7 donors per million people.

As I noted two weeks ago,
the Campaign for Responsible Transplantation attacked Americans for Medical Progress for highlighting former Chicago Bear running back Walter Payton’s
recent announcement that he has a rare fatal liver disease. The CRT attack
on AMP, however, seemed like an act of desperation. They tried to throw
everything but the kitchen sink at AMP – xenotransplantation might not
work, it poses a risk of transmitting disease across species, it could
be avoided by increasing the donor pool, etc.

There are many responses to
these claims (CRT doesn’t seem to keep up with recent scientific advancements
in genetic engineering) but as far as I can tell the bottom line is this:
animal rights activism in the medical experimentation field has been successful
largely to the extent that it has engaged people’s sympathies against
hurting animals, especially unnecessarily. But that play on emotionalism
is a double-edged sword, since most people are openly “speciesist”
who, when it comes down to it, will find the suffering and pain of Walter
Payton far more compelling and worthy of alleviation than that of a pig
whose death could save Payton’s life.

What seems to anger CRT to
no end is that AMP gave them a taste of their own medicine with their
focus on Payton. I say more power to them.

Calnan’s op-ed, “Payton’s
hope” (available at http://amprogress.org/news/payton.htm) highlighted the problems of former Chicago Bear running back Walter
Payton, who recently announced he has a rare liver disease and may die
within two years if he does not receive a transplant.

As Calnan noted in her op-ed,
although there are 12,000 people on the waiting list for livers, only
about 4,000 such transplants are performed each year. In 1997 more than
1,000 people died while waiting for a matching liver. Calnan’s editorial
did an excellent job of highlighting animal rights hypocrisy, which is
why I suspect it was so quickly attacked. She repeated PETA celebrity
spokesman Bill Maher‘s recent quote to US Magazine that: “To those
people who say, ‘My father is alive because of animal experimentation,’
I say ‘Yeah, well, good for you. This dog died so your father could live.’
Sorry, but I am just not behind that kind of trade off.” Someone
should send Maher a thank you note for so succinctly summing up the animal
rights philosophy.

Calnan mentioned the newly
developed device I mentioned a couple weeks ago that uses pig cells to
help keep some people alive while waiting transplants. The fact is this
technology is here today and it is already saving lives, so the animal
rights and extreme environmental activists have to fall back on two claims
to discredit the technology.

The first is that the risk
of passing diseases from non-humans to humans is too high. Animal rights
activists have released claim after claim trying to make this point, but
most of the more serious ones have later turned out to be baseless. On
the other hand, like any other thing human beings do, there is always
some risk associated with it – the risk of some new deadly disease crossing
from non-humans to humans will never be zero.

But if our society was that
risk-averse no pharmaceutical drugs or medical technology would ever be
approved since the risk of a calamity from any new technology is never
zero. If this sort of principle actually guided medical technology, certainly
technologies that we take for granted, such as vaccination, would never
have been allowed since the potential risks were only poorly known at best.

The second claim is that there
are more than enough organ donors to go around. At the end of her article,
Calnan ask for more people to become organ donors, which is a reasonable
position, but the critics of xenotransplantation seem to assume that those
organ donors are here today. A recent press release from the Boston-basedCampaign for Responsible Transplantation claimed, for example, that Xenotransplantation
advocates “use statistics and emotion to make their case … some 3,000
transplant patients die each year on in the U.S. … [but a ] US General
Accounting Office report … reveals a potential organ donor pool of 150,000
people. This is in stark contrast to previous estimates of 5,000 to 29,000
people annually … if these organs are secured, it would solve the national
organ shortage, and completely eliminate the need for animal organ transplants.”

As is the typical modus operandi with
these groups, however, this last claim is a distortion. The GAO report
was written to explore different methods of evaluating the performance
of Organ Procurement Organizations, who are assigned the task of procuring
organs and getting them into the organ sharing network. In order to do
that sort of evaluation, the GAO wanted a baseline of the upper bound of
eligible organ donors, which it estimated at 147,000 in 1994 using a technique
to estimate actual deaths and then adjust the figures to determine how
many of those deaths would have had harvestable organs.

The interesting thing is that
in the very next paragraph after giving this estimate, the GAO notes the
limits of counting potential organs this way, “we found that both
the death and adjusted-death measures [which are the source of the 147,000
figure] have drawbacks that limit their usefulness, however, including
lack of timely data and inability to identify those deaths suitable for
use in organ donation.”

First, this explicitly concedes
that the 147,000 figure was obtained using a method that the GAO admits
has an “inability to identify those deaths suitable for use in organ
donation,” which is the crux of the problem with human organ donation
itself. If it was too expensive and time consuming for the GAO to go back
four years and decide how many people were eligible organ donors,
imagine the difficulty in trying to harvest those organs on the spot.

It is one thing to look back
several years later and say there were say 40,000 automobile deaths and
of those 6,000 were potential organ donors. It is another thing to be
in place to actually obtain those organs (a severe problem in organ donation
is that even among those who have signed organ donor cards and are good candidates
to donate organs, often the organs are no longer usable by the time doctors
are aware of the potential donor or get permission from family members
to proceed. This is a situation that is unlikely to change significantly
in the near future).

In addition, the CRT release
failed to note that the number organ donors has increased over the last
few years – but the number of people eligible for organ donation has increased
even faster. I suppose if PETA had its way, this wouldn’t be a problem
since there would be no animal research and fewer people would be transplant
candidates since the medical knowledge to save their lives simply wouldn’t
exist, but barring this it seems clear that future advances in medical
science are going to continue to drive the demand for organ donation at
a much faster rate than the increase in donated organs.

If anything the GAO report
on the failures of Organ Procurement Organizations to obtain more organs
is evidence of just how difficult it is going to be to increase the level
of organ donation, and further emphasizes why xenotransplantation and
similar technologies will likely play a key role in the 21st century – provided animal rights activists aren’t given the chance to
halt this important advance.